A network is a collection of computers and devices connected to each other. The network allows computers to communicate with each other and share resources and information.Or A network is a group of computers, printers, and other devices that are connected together with cables. Information travels over the cables, allowing network users to exchange documents & data with each other, print to the same printers, and generally share any hardware or software that is connected to the network. Each computer, printer, or other peripheral device that is connected to the network is called a node.
For making one Network minimum size of Computers should be 2, while maximumThere could be Millions of Computer. In one netwo6rk there could be different ComputerAnd different NOS (Network Operating System).
The Advance Research Projects Agency (ARPA) designed "Advanced Research Projects Agency Network" (ARPANET) for the United States Department of Defense. It was the first computer network in the world in late 1960's and early 1970's.
Thursday, February 26, 2009
Benefits of Making Networks
§ Fast Communication
§ Sharing data
§ Sharing Resources (Printer, Scanner, Optical Drives, Magnetical Drives etc)
§ Cost effective (by using one device by many computers)
§ Security (Domain)
§ Centralize Administration
§ Electronic Mail
§ Electronic Commerce
§ And many more.
§ Sharing data
§ Sharing Resources (Printer, Scanner, Optical Drives, Magnetical Drives etc)
§ Cost effective (by using one device by many computers)
§ Security (Domain)
§ Centralize Administration
§ Electronic Mail
§ Electronic Commerce
§ And many more.
Resources for making a Network
§ Computers
§ LAN Cards/NIC/Ethernet Card
§ Media (Cable, Waves)
§ Connectors (BNC, AUI, RJ45, Fiber Clips)
§ HUB/Switch (Star Topology)
§ Router (in case of WAN)
§ NOS (Network Operating System)
§ LAN Cards/NIC/Ethernet Card
§ Media (Cable, Waves)
§ Connectors (BNC, AUI, RJ45, Fiber Clips)
§ HUB/Switch (Star Topology)
§ Router (in case of WAN)
§ NOS (Network Operating System)
Types of Network According Area
1: LAN (Local Area Network)
2: MAN (Metropolitan Area Network)
3: WAN (Wide Area Network)
LAN
A Local Area Network is the Network of different Computers in well defines and Small Area like a Network of any organization in one building or cluster of buildings But should be with in 1KM.
MAN
A Metropolitan Area Network is the Network of different remote access buildings
In one city. A city can be large and small. OR the Network of different LANs in one City is called MAN.
WAN
A wide Area Network is Network of different LANs which exist in different cities or Different countries.
2: MAN (Metropolitan Area Network)
3: WAN (Wide Area Network)
LAN
A Local Area Network is the Network of different Computers in well defines and Small Area like a Network of any organization in one building or cluster of buildings But should be with in 1KM.
MAN
A Metropolitan Area Network is the Network of different remote access buildings
In one city. A city can be large and small. OR the Network of different LANs in one City is called MAN.
WAN
A wide Area Network is Network of different LANs which exist in different cities or Different countries.
Types of Network According to Configuration
1: Workgroup (Peer to Peer Network)
2: Domain (Server Based Network)
Workgroup (Peer to Peer Network)
Ø In this type of Network there is no dedicated (specific) Server.
Ø Every Computer is Server and Client at the same time.
Ø In this network every user is responsible for the security of their System.
Ø Every Computer is known as a Workstation.
Ø No workstation can assign any restriction on any other workstation.
Ø The recommended size of Computers is 10 for this Network. But we can
Connect more then 10 Computers.
Ø Peer to Peer Network is good for sharing of Software and Resources, but there
No security.
Domain (Sever Based Network)
Ø In this type of Network there is a dedicated server which is responsible for the
Ø Management of all other Computers in the Network which are called Clients.
Ø In a Domain all security is centrally administrated by the Server.
Ø Server is responsible to share different kinds of Resources and Software to every Client Computer.
Ø No Client Computer can log on in the Network without the permission of
Server.
Ø A server based network may have thousands of Computers.
2: Domain (Server Based Network)
Workgroup (Peer to Peer Network)
Ø In this type of Network there is no dedicated (specific) Server.
Ø Every Computer is Server and Client at the same time.
Ø In this network every user is responsible for the security of their System.
Ø Every Computer is known as a Workstation.
Ø No workstation can assign any restriction on any other workstation.
Ø The recommended size of Computers is 10 for this Network. But we can
Connect more then 10 Computers.
Ø Peer to Peer Network is good for sharing of Software and Resources, but there
No security.
Domain (Sever Based Network)
Ø In this type of Network there is a dedicated server which is responsible for the
Ø Management of all other Computers in the Network which are called Clients.
Ø In a Domain all security is centrally administrated by the Server.
Ø Server is responsible to share different kinds of Resources and Software to every Client Computer.
Ø No Client Computer can log on in the Network without the permission of
Server.
Ø A server based network may have thousands of Computers.
Types of Network According to Configuration
1: Workgroup (Peer to Peer Network)
2: Domain (Server Based Network)
Workgroup (Peer to Peer Network)
Ø In this type of Network there is no dedicated (specific) Server.
Ø Every Computer is Server and Client at the same time.
Ø In this network every user is responsible for the security of their System.
Ø Every Computer is known as a Workstation.
Ø No workstation can assign any restriction on any other workstation.
Ø The recommended size of Computers is 10 for this Network. But we can
Connect more then 10 Computers.
Ø Peer to Peer Network is good for sharing of Software and Resources, but there
No security.
Domain (Sever Based Network)
Ø In this type of Network there is a dedicated server which is responsible for the
Ø Management of all other Computers in the Network which are called Clients.
Ø In a Domain all security is centrally administrated by the Server.
Ø Server is responsible to share different kinds of Resources and Software to every Client Computer.
Ø No Client Computer can log on in the Network without the permission of
Server.
Ø A server based network may have thousands of Computers.
2: Domain (Server Based Network)
Workgroup (Peer to Peer Network)
Ø In this type of Network there is no dedicated (specific) Server.
Ø Every Computer is Server and Client at the same time.
Ø In this network every user is responsible for the security of their System.
Ø Every Computer is known as a Workstation.
Ø No workstation can assign any restriction on any other workstation.
Ø The recommended size of Computers is 10 for this Network. But we can
Connect more then 10 Computers.
Ø Peer to Peer Network is good for sharing of Software and Resources, but there
No security.
Domain (Sever Based Network)
Ø In this type of Network there is a dedicated server which is responsible for the
Ø Management of all other Computers in the Network which are called Clients.
Ø In a Domain all security is centrally administrated by the Server.
Ø Server is responsible to share different kinds of Resources and Software to every Client Computer.
Ø No Client Computer can log on in the Network without the permission of
Server.
Ø A server based network may have thousands of Computers.
Types of Network According to Configuration
1: Workgroup (Peer to Peer Network)
2: Domain (Server Based Network)
Workgroup (Peer to Peer Network)
Ø In this type of Network there is no dedicated (specific) Server.
Ø Every Computer is Server and Client at the same time.
Ø In this network every user is responsible for the security of their System.
Ø Every Computer is known as a Workstation.
Ø No workstation can assign any restriction on any other workstation.
Ø The recommended size of Computers is 10 for this Network. But we can
Connect more then 10 Computers.
Ø Peer to Peer Network is good for sharing of Software and Resources, but there
No security.
Domain (Sever Based Network)
Ø In this type of Network there is a dedicated server which is responsible for the
Ø Management of all other Computers in the Network which are called Clients.
Ø In a Domain all security is centrally administrated by the Server.
Ø Server is responsible to share different kinds of Resources and Software to every Client Computer.
Ø No Client Computer can log on in the Network without the permission of
Server.
Ø A server based network may have thousands of Computers.
2: Domain (Server Based Network)
Workgroup (Peer to Peer Network)
Ø In this type of Network there is no dedicated (specific) Server.
Ø Every Computer is Server and Client at the same time.
Ø In this network every user is responsible for the security of their System.
Ø Every Computer is known as a Workstation.
Ø No workstation can assign any restriction on any other workstation.
Ø The recommended size of Computers is 10 for this Network. But we can
Connect more then 10 Computers.
Ø Peer to Peer Network is good for sharing of Software and Resources, but there
No security.
Domain (Sever Based Network)
Ø In this type of Network there is a dedicated server which is responsible for the
Ø Management of all other Computers in the Network which are called Clients.
Ø In a Domain all security is centrally administrated by the Server.
Ø Server is responsible to share different kinds of Resources and Software to every Client Computer.
Ø No Client Computer can log on in the Network without the permission of
Server.
Ø A server based network may have thousands of Computers.
Types of Network According to Configuration
1: Workgroup (Peer to Peer Network)
2: Domain (Server Based Network)
Workgroup (Peer to Peer Network)
Ø In this type of Network there is no dedicated (specific) Server.
Ø Every Computer is Server and Client at the same time.
Ø In this network every user is responsible for the security of their System.
Ø Every Computer is known as a Workstation.
Ø No workstation can assign any restriction on any other workstation.
Ø The recommended size of Computers is 10 for this Network. But we can
Connect more then 10 Computers.
Ø Peer to Peer Network is good for sharing of Software and Resources, but there
No security.
Domain (Sever Based Network)
Ø In this type of Network there is a dedicated server which is responsible for the
Ø Management of all other Computers in the Network which are called Clients.
Ø In a Domain all security is centrally administrated by the Server.
Ø Server is responsible to share different kinds of Resources and Software to every Client Computer.
Ø No Client Computer can log on in the Network without the permission of
Server.
Ø A server based network may have thousands of Computers.
2: Domain (Server Based Network)
Workgroup (Peer to Peer Network)
Ø In this type of Network there is no dedicated (specific) Server.
Ø Every Computer is Server and Client at the same time.
Ø In this network every user is responsible for the security of their System.
Ø Every Computer is known as a Workstation.
Ø No workstation can assign any restriction on any other workstation.
Ø The recommended size of Computers is 10 for this Network. But we can
Connect more then 10 Computers.
Ø Peer to Peer Network is good for sharing of Software and Resources, but there
No security.
Domain (Sever Based Network)
Ø In this type of Network there is a dedicated server which is responsible for the
Ø Management of all other Computers in the Network which are called Clients.
Ø In a Domain all security is centrally administrated by the Server.
Ø Server is responsible to share different kinds of Resources and Software to every Client Computer.
Ø No Client Computer can log on in the Network without the permission of
Server.
Ø A server based network may have thousands of Computers.
Types of Network According to Configuration
1: Workgroup (Peer to Peer Network)
2: Domain (Server Based Network)
Workgroup (Peer to Peer Network)
Ø In this type of Network there is no dedicated (specific) Server.
Ø Every Computer is Server and Client at the same time.
Ø In this network every user is responsible for the security of their System.
Ø Every Computer is known as a Workstation.
Ø No workstation can assign any restriction on any other workstation.
Ø The recommended size of Computers is 10 for this Network. But we can
Connect more then 10 Computers.
Ø Peer to Peer Network is good for sharing of Software and Resources, but there
No security.
Domain (Sever Based Network)
Ø In this type of Network there is a dedicated server which is responsible for the
Ø Management of all other Computers in the Network which are called Clients.
Ø In a Domain all security is centrally administrated by the Server.
Ø Server is responsible to share different kinds of Resources and Software to every Client Computer.
Ø No Client Computer can log on in the Network without the permission of
Server.
Ø A server based network may have thousands of Computers.
2: Domain (Server Based Network)
Workgroup (Peer to Peer Network)
Ø In this type of Network there is no dedicated (specific) Server.
Ø Every Computer is Server and Client at the same time.
Ø In this network every user is responsible for the security of their System.
Ø Every Computer is known as a Workstation.
Ø No workstation can assign any restriction on any other workstation.
Ø The recommended size of Computers is 10 for this Network. But we can
Connect more then 10 Computers.
Ø Peer to Peer Network is good for sharing of Software and Resources, but there
No security.
Domain (Sever Based Network)
Ø In this type of Network there is a dedicated server which is responsible for the
Ø Management of all other Computers in the Network which are called Clients.
Ø In a Domain all security is centrally administrated by the Server.
Ø Server is responsible to share different kinds of Resources and Software to every Client Computer.
Ø No Client Computer can log on in the Network without the permission of
Server.
Ø A server based network may have thousands of Computers.
NOS (Network Operating System)
Workstation O.S Client O.S Server O.S
Windows NT Workstation Windows NT Workstation Win NT Server
Windows 95 Windows 2000 Professional Win 2000 Server
Windows 97 Windows XP Professional Win 2003 Server
Windows 98 UNIX
Windows 2000 professional Linux
Windows XP professional Novel Netware
Windows NT Workstation Windows NT Workstation Win NT Server
Windows 95 Windows 2000 Professional Win 2000 Server
Windows 97 Windows XP Professional Win 2003 Server
Windows 98 UNIX
Windows 2000 professional Linux
Windows XP professional Novel Netware
Media
The way on which data travels from Source Computer to the Destination Computer is called Media OR the object which makes a link between Sender and Receiver.
Types of Media
1: Guided Media (Bounded Media)
2: Unguided Media (Unbounded Media)
1: Guided Media: (Cables)
We have three types of Guided Media
1 Coaxial Cable
2 Twisted Pair Cable
3 Fiber Optic Cable
Coaxial Cable
There are two types of Coaxial Cable
Thin net Coaxial Cable
Thick net Coaxial Cable
Thin net Coaxial (10 base 2)
Ø It is used in base band transmission
Ø It can flow the data up to 185 to 200 Meter
Ø We use this type cable in Bus Topology and Ring Topology
Ø It has a speed of 10 Mbps (Mega bit per second)
Ø The connector for this cable is called BNC (British Naval Connector)
Thick net Coaxial (10 base 5)
Ø It is used in base band transmission.
Ø It can flow the data up to 500 meter.
Ø It is used in Bus and Ring Topology.
Ø It has a speed of 10 Mbps
Ø The connector for this cable is called AUI (Attachment Unit Interface)
Twisted Pair Cable
STP (Shielded Twisted Pair Cable)
UTP (Unshielded Twisted Pair Cable)
There are six Categories available in Twisted Pair Cable
Types of Media
1: Guided Media (Bounded Media)
2: Unguided Media (Unbounded Media)
1: Guided Media: (Cables)
We have three types of Guided Media
1 Coaxial Cable
2 Twisted Pair Cable
3 Fiber Optic Cable
Coaxial Cable
There are two types of Coaxial Cable
Thin net Coaxial Cable
Thick net Coaxial Cable
Thin net Coaxial (10 base 2)
Ø It is used in base band transmission
Ø It can flow the data up to 185 to 200 Meter
Ø We use this type cable in Bus Topology and Ring Topology
Ø It has a speed of 10 Mbps (Mega bit per second)
Ø The connector for this cable is called BNC (British Naval Connector)
Thick net Coaxial (10 base 5)
Ø It is used in base band transmission.
Ø It can flow the data up to 500 meter.
Ø It is used in Bus and Ring Topology.
Ø It has a speed of 10 Mbps
Ø The connector for this cable is called AUI (Attachment Unit Interface)
Twisted Pair Cable
STP (Shielded Twisted Pair Cable)
UTP (Unshielded Twisted Pair Cable)
There are six Categories available in Twisted Pair Cable
RJ: Registered Jack
Making of Twisted Pair Cable
We make Twisted Pair Cable in three different ways for Network
1: Cross Cable
2: Straight Cable
3: Roll Over Cable
Cross Cable
Cross Cable is used to connect two same devices like Computer to Computer, hub to Hub or Switch to Switch
Straight Cable
This type of cable is used to connect different devices .It is also used in Star topology. It is used to connect Computer to Hub, Computer to Switch or switch to Router (MAN or WAN)
Roll Over Cable
This type of cable is used to only and only connect Computer to Router; we connect system to Router in order to configuration the Router by the help of IOS (Internet work Operating System).
We have two Standards to make the above three Cables. 568A and 568B
Cross Cable
568A _________________568B
Straight Cable
568A ___________________568A
568B ___________________ 568B
Roll Over Cable
568A ____________________ 568 A-1
Fiber Optic Cable
It is used in LAN, MAN, WAN.
The speed of this cable is up to 2000 Mbps.
It can Flow the Data up to 10 KM.
In the cable instead of conductor there is glass or plastic covered by Fibers.
Data flows in the form of Light.
Light is encoding in digital signals.
It is used in base band transmission.
The connector for this cable is called Fiber Clip.
Topology
The physical arrangement of Computers is called Topology OR the physical
Connectivity of different computers via different cables is called topology.
Types of Topology
1: Bus Topology
2: Ring Topology
3 Star Topology
4: Mesh Topology
Bus Topology
In Bus Topology all Computers on the Network are connected to a single cable called Bus. Coaxial cable is used in this topology. The bus topology is easy to install and the cost is usually lower then for other network topologies. But the cable failure shuts down the network, and it can be extremely difficult to locate broken cables on large Networks. Only one Computer can send the data at one time via bus. Data goes to every computer on the way of the destination computer.
Star Topology
In star topology each computer is connected to a central device with its own dedicated cable. The central device is called Hub and Switch. Every computer can send the data at one time. Troubleshooting is easy .In the case of failure of any cable only one computer get disconnects.
Connectivity of different computers via different cables is called topology.
Types of Topology
1: Bus Topology
2: Ring Topology
3 Star Topology
4: Mesh Topology
Bus Topology
In Bus Topology all Computers on the Network are connected to a single cable called Bus. Coaxial cable is used in this topology. The bus topology is easy to install and the cost is usually lower then for other network topologies. But the cable failure shuts down the network, and it can be extremely difficult to locate broken cables on large Networks. Only one Computer can send the data at one time via bus. Data goes to every computer on the way of the destination computer.
Ring Topology
In ring topology we connect all computers in the form of a ring with the help of a single coaxial cable. Last Computer is connected to first computer. Both way communications is possible. Ring topology is easy to install, but in the case of failure of any 1 computer all network get disconnect.
Star Topology
In star topology each computer is connected to a central device with its own dedicated cable. The central device is called Hub and Switch. Every computer can send the data at one time. Troubleshooting is easy .In the case of failure of any cable only one computer get disconnects.
Mesh Topology
In mesh topology every computer is connected to every other computer in the network. A lot of cable is used in this network. Coaxial bale is used for connectivity.
Network Devices
1: LAN Card (Local Area Network Card)
It is also called NIC (Network Interface Card). It is used to connect a computer to a Local Area Network. LAN cards are available in different port like AUI, BNC and RJ45.
2: MODEM (Modulator and Demodulator)
It is used for conversion of digital data into analog data (modulation) and analog data in digital data (demodulation).it is used to connect a computer to inter network via telephone line it has RJ 11 port.
3: HUB
It is a centralized device .it is used to make a link between different computers in star topology. It has no addressing scheme. It is used to broad cast the data. It takes the data from one computer and sends that to all other computer, and then at last the destination computer receives the data.
3: Switch
It is used as a centralized device in star topology. All computer are connected with each other via switch in star topology .it has addressing scheme. It is used to unicast the data. It takes the data from one computer and sends that data direct to the destination computer.
4: Router
It is used to connect different Network with each other. It is used in MAN and WAN to connect two remote access Networks .In WAN every Network should has a Router. We connect a computer to the router with the help of roll over cable in order to configure the Router by the help of IOS (Inter Network Operating System).
It is also called NIC (Network Interface Card). It is used to connect a computer to a Local Area Network. LAN cards are available in different port like AUI, BNC and RJ45.
2: MODEM (Modulator and Demodulator)
It is used for conversion of digital data into analog data (modulation) and analog data in digital data (demodulation).it is used to connect a computer to inter network via telephone line it has RJ 11 port.
3: HUB
It is a centralized device .it is used to make a link between different computers in star topology. It has no addressing scheme. It is used to broad cast the data. It takes the data from one computer and sends that to all other computer, and then at last the destination computer receives the data.
3: Switch
It is used as a centralized device in star topology. All computer are connected with each other via switch in star topology .it has addressing scheme. It is used to unicast the data. It takes the data from one computer and sends that data direct to the destination computer.
4: Router
It is used to connect different Network with each other. It is used in MAN and WAN to connect two remote access Networks .In WAN every Network should has a Router. We connect a computer to the router with the help of roll over cable in order to configure the Router by the help of IOS (Inter Network Operating System).
Protocol
The set of rules which is used to exchange data between different computer and
Different Operating systems in a network.
OR, the language with is used to exchange data between the different computers in
A network is called protocol.
Without protocol computers can’t communicate between each other.
Types of Protocol
1: NETBEUI (NetBIOS Extended User Interface)
This protocol can only communicate between the computers having any operating
System of Microsoft.
2: IPX/SPX (Internet Packet Exchange /Simple Packet Exchange)
This is the protocol of Novel Netware (NOS) .this protocol can only communicate
Between the computers having the Novel Netware.
3: TCP / IP (Transmission Control Protocol / Internet Protocol)
This is universal Protocol .It can communicate between all types of Operating
Systems. It is also using in Inter Network Communication.
Different Operating systems in a network.
OR, the language with is used to exchange data between the different computers in
A network is called protocol.
Without protocol computers can’t communicate between each other.
Types of Protocol
1: NETBEUI (NetBIOS Extended User Interface)
This protocol can only communicate between the computers having any operating
System of Microsoft.
2: IPX/SPX (Internet Packet Exchange /Simple Packet Exchange)
This is the protocol of Novel Netware (NOS) .this protocol can only communicate
Between the computers having the Novel Netware.
3: TCP / IP (Transmission Control Protocol / Internet Protocol)
This is universal Protocol .It can communicate between all types of Operating
Systems. It is also using in Inter Network Communication.
IP Addressing
It is the address scheme of TCP/IP protocol. We can assign IP address to every Computer in case of TCP/IP protocol. So that if any computer wants to connect.To another computer in the network it connects with the help of IP address.
It is a 32 bit address which is divided into 4 octets. 1 octet is consisting of 8 bits.
It is a 32 bit address which is divided into 4 octets. 1 octet is consisting of 8 bits.
We assign IP address in decimal numbers.
We classify IP address in three classes.
Class Range
Class A 1-126
Class B 128-191
Class C 192-223
127 is reserved IP address, it is also called Lope back IP address. It is used in troubleshooting and to check connectivity.
In Network ID we write the address of Network while in Host ID we write The address of the Computer.
We classify IP address in three classes.
Class Range
Class A 1-126
Class B 128-191
Class C 192-223
127 is reserved IP address, it is also called Lope back IP address. It is used in troubleshooting and to check connectivity.
In Network ID we write the address of Network while in Host ID we write The address of the Computer.
Subnet Mask Address
We assign a subnet mask address to every IP address. This address is used to
Define Network ID and Host ID in an IP address.
We put 255 for network ID and 0 for host id in a subnet mask address.
For Exp:
IP Addres : 50 . 0 . 0 . 1
Subnet Mask : 255 . 0 . 0 . 0
IP Addres : 130 . 0 . 0 . 25
Subnet Mask : 255 . 255 . 0 . 0
IP Addres : 215 . 0 . 0 .10
Subnet Mask : 255 . 255 . 255 .0
Define Network ID and Host ID in an IP address.
We put 255 for network ID and 0 for host id in a subnet mask address.
For Exp:
IP Addres : 50 . 0 . 0 . 1
Subnet Mask : 255 . 0 . 0 . 0
IP Addres : 130 . 0 . 0 . 25
Subnet Mask : 255 . 255 . 0 . 0
IP Addres : 215 . 0 . 0 .10
Subnet Mask : 255 . 255 . 255 .0
Wednesday, February 25, 2009
OSI Model
The Open Systems Interconnection Reference Model (OSI Reference Model or OSI Model) is an abstract description for layered communications and computer network protocol design. It was developed as part of the Open Systems Interconnection (OSI) initiative.[1] In its most basic form, it divides network architecture into seven layers which, from top to bottom, are the Application, Presentation, Session, Transport, Network, Data-Link, and Physical Layers. It is therefore often referred to as the OSI Seven Layer Model.
A layer is a collection of conceptually similar functions that provide services to the layer above it and receives service from the layer below it. For example, a layer that provides error-free communications across a network provides the path needed by applications above it, while it calls the next lower layer to send and receive packets that make up the contents of the path.
Contents
1 History
2 Description of OSI layers
2.1 Layer 7: Application Layer
2.2 Layer 6: Presentation Layer
2.3 Layer 5: Session Layer
2.4 Layer 4: Transport Layer
2.5 Layer 3: Network Layer
2.6 Layer 2: Data Link Layer
2.6.1 WAN Protocol architecture
2.6.2 IEEE 802 LAN architecture
2.7 Layer 1: Physical Layer
History
In 1977, 2work on a layered model of network architecture was started, and the International Organization for Standardization (ISO) began to develop its OSI framework architecture. OSI has two major components: an abstract model of networking, called the Basic Reference Model or seven-layer model, and a set of specific protocols.
Note: The standard documents that describe the OSI model can be freely downloaded from the ITU-T as the X.200-series of recommendations.[2] A number of the protocol specifications are also available as part of the ITU-T X series. The equivalent ISO and ISO/IEC standards for the OSI model are available from the ISO, but only some of the ISO/IEC standards are available as cost-free downloads.[3]
All aspects of OSI design evolved from experiences with the CYCLADES network, which also influenced Internet design. The new design was documented in ISO 7498 and its various addenda. In this model, a networking system is divided into layers. Within each layer, one or more entities implement its functionality. Each entity interacts directly only with the layer immediately beneath it, and provides facilities for use by the layer above it.
Protocols enable an entity in one host to interact with a corresponding entity at the same layer in another host. Service definitions abstractly describe the functionality provided to an (N)-layer by an (N-1) layer, where N is one of the seven layers of protocols operating in the local host.
Description of OSI layers
Layer 7: Application Layer
Main article: Application Layer
The application layer is the OSI layer closest to the end user, which means that both the OSI application layer and the user interact directly with the software application. This layer interacts with software applications that implement a communicating component. Such application programs fall outside the scope of the OSI model. Application layer functions typically include identifying communication partners, determining resource availability, and synchronizing communication. When identifying communication partners, the application layer determines the identity and availability of communication partners for an application with data to transmit. When determining resource availability, the application layer must decide whether sufficient network resources for the requested communication exist. In synchronizing communication, all communication between applications requires cooperation that is managed by the application layer. Some examples of application layer implementations include Telnet, Hypertext Transfer Protocol (HTTP), File Transfer Protocol (FTP) , and Simple Mail Transfer Protocol (SMTP).
Layer 6: Presentation Layer
Main article: Presentation Layer
The Presentation Layer establishes a context between Application Layer entities, in which the higher-layer entities can use different syntax and semantics, as long as the Presentation Service understands both and the mapping between them. The presentation service data units are then encapsulated into Session Protocol Data Units, and moved down the stack.
This layer provides independence from differences in data representation (e.g., encryption) by translating from application to network format, and vice versa. The presentation layer works to transform data into the form that the application layer can accept. This layer formats and encrypts data to be sent across a network, providing freedom from compatibility problems. It is sometimes called the syntax layer.
The original presentation structure used the Basic Encoding Rules of Abstract Syntax Notation One (ASN.1), with capabilities such as converting an EBCDIC-coded text file to an ASCII-coded file, or serializing objects and other data structures into and out of XML. ASN.1 has a set of cryptographic encoding rules that allows end-to-end encryption between application entities.
[edit] Layer 5: Session Layer
Main article: Session Layer
The Session Layer controls the dialogues (connections) between computers. It establishes, manages and terminates the connections between the local and remote application. It provides for full-duplex, half-duplex, or simplex operation, and establishes checkpointing, adjournment, termination, and restart procedures. The OSI model made this layer responsible for "graceful close" of sessions, which is a property of TCP, and also for session checkpointing and recovery, which is not usually used in the Internet Protocol Suite. The Session Layer is commonly implemented explicitly in application environments that use remote procedure calls (RPCs).
Layer 4: Transport Layer
Main article: Transport Layer
The Transport Layer provides transparent transfer of data between end users, providing reliable data transfer services to the upper layers. The Transport Layer controls the reliability of a given link through flow control, segmentation/desegmentation, and error control. Some protocols are state and connection oriented. This means that the Transport Layer can keep track of the segments and retransmit those that fail.
Although not developed under the OSI Reference Model and not strictly conforming to the OSI definition of the Transport Layer, the best known examples of a Layer 4 protocol are the Transmission Control Protocol (TCP) and User Datagram Protocol (UDP).[citation needed]
Of the actual OSI protocols, there are five classes of transport protocols ranging from class 0 (which is also known as TP0 and provides the least error recovery) to class 4 (which is also known as TP4 and is designed for less reliable networks, similar to the Internet). Class 0 contains no error recovery, and was designed for use on network layers that provide error-free connections. Class 4 is closest to TCP, although TCP contains functions, such as the graceful close, which OSI assigns to the Session Layer. Detailed characteristics of TP0-4 classes are shown in the following table.
Perhaps an easy way to visualize the Transport Layer is to compare it with a Post Office, which deals with the dispatch and classification of mail and parcels sent. Do remember, however, that a post office manages the outer envelope of mail. Higher layers may have the equivalent of double envelopes, such as cryptographic presentation services that can be read by the addressee only. Roughly speaking, tunneling protocols operate at the Transport Layer, such as carrying non-IP protocols such as IBM's SNA or Novell's IPX over an IP network, or end-to-end encryption with IPsec. While Generic Routing Encapsulation (GRE) might seem to be a Network Layer protocol, if the encapsulation of the payload takes place only at endpoint, GRE becomes closer to a transport protocol that uses IP headers but contains complete frames or packets to deliver to an endpoint. L2TP carries PPP frames inside transport packet.
Layer 3: Network Layer
Main article: Network Layer
The Network Layer provides the functional and procedural means of transferring variable length data sequences from a source to a destination via one or more networks, while maintaining the quality of service requested by the Transport Layer. The Network Layer performs network routing functions, and might also perform fragmentation and reassembly, and report delivery errors. Routers operate at this layer—sending data throughout the extended network and making the Internet possible. This is a logical addressing scheme – values are chosen by the network engineer. The addressing scheme is hierarchical.
The best-known example of a Layer 3 protocol is the Internet Protocol (IP). It manages the connectionless transfer of data one hop at a time, from end system to ingress router, router to router, and from egress router to destination end system. It is not responsible for reliable delivery to a next hop, but only for the detection of errored packets so they may be discarded. When the medium of the next hop cannot accept a packet in its current length, IP is responsible for fragmenting the packet into sufficiently small packets that the medium can accept.
A number of layer management protocols, a function defined in the Management Annex, ISO 7498/4, belong to the Network Layer. These include routing protocols, multicast group management, Network Layer information and error, and Network Layer address assignment. It is the function of the payload that makes these belong to the Network Layer, not the protocol that carries them.
Layer 2: Data Link Layer
Main article: Data Link Layer
The Data Link Layer provides the functional and procedural means to transfer data between network entities and to detect and possibly correct errors that may occur in the Physical Layer. Originally, this layer was intended for point-to-point and point-to-multipoint media, characteristic of wide area media in the telephone system. Local area network architecture, which included broadcast-capable multiaccess media, was developed independently of the ISO work, in IEEE Project 802. IEEE work assumed sublayering and management functions not required for WAN use. In modern practice, only error detection, not flow control using sliding window, is present in modern data link protocols such as Point-to-Point Protocol (PPP), and, on local area networks, the IEEE 802.2 LLC layer is not used for most protocols on Ethernet, and, on other local area networks, its flow control and acknowledgment mechanisms are rarely used. Sliding window flow control and acknowledgment is used at the Transport Layer by protocols such as TCP, but is still used in niches where X.25 offers performance advantages.
Both WAN and LAN services arrange bits, from the Physical Layer, into logical sequences called frames. Not all Physical Layer bits necessarily go into frames, as some of these bits are purely intended for Physical Layer functions. For example, every fifth bit of the FDDI bit stream is not used by the Layer.
WAN Protocol architecture
Connection-oriented WAN data link protocols, in addition to framing, detect and may correct errors. They also are capable of controlling the rate of transmission. A WAN Data Link Layer might implement a sliding window flow control and acknowledgment mechanism to provide reliable delivery of frames; that is the case for SDLC and HDLC, and derivatives of HDLC such as LAPB and LAPD.
IEEE 802 LAN architecture
Practical, connectionless LANs began with the pre-IEEE Ethernet specification, which is the ancestor of IEEE 802.3. This layer manages the interaction of devices with a shared medium, which is the function of a Media Access Control sublayer. Above this MAC sublayer is the media-independent IEEE 802.2 Logical Link Control (LLC) sublayer, which deals with addressing and multiplexing on multiaccess media.
While IEEE 802.3 is the dominant wired LAN protocol and IEEE 802.11 the wireless LAN protocol, obsolescent MAC layers include Token Ring and FDDI. The MAC sublayer detects but does not correct errors.
Layer 1: Physical Layer
Main article: Physical Layer
The Physical Layer defines the electrical and physical specifications for devices. In particular, it defines the relationship between a device and a physical medium. This includes the layout of pins, voltages, cable specifications, Hubs, repeaters, network adapters, Host Bus Adapters (HBAs used in Storage Area Networks) and more.
To understand the function of the Physical Layer in contrast to the functions of the Data Link Layer, think of the Physical Layer as concerned primarily with the interaction of a single device with a medium, where the Data Link Layer is concerned more with the interactions of multiple devices (i.e., at least two) with a shared medium. The Physical Layer will tell one device how to transmit to the medium, and another device how to receive from it (in most cases it does not tell the device how to connect to the medium). Standards such as RS-232 do use physical wires to control access to the medium.
The major functions and services performed by the Physical Layer are:--
Establishment and termination of a connection to a communications medium.
Participation in the process whereby the communication resources are effectively shared among multiple users. For example, contention resolution and flow control.
Modulation, or conversion between the representation of digital data in user equipment and the corresponding signals transmitted over a communications channel. These are signals operating over the physical cabling (such as copper and optical fiber) or over a radio link.
Parallel SCSI buses operate in this layer, although it must be remembered that the logical SCSI protocol is a Transport Layer protocol that runs over this bus. Various Physical Layer Ethernet standards are also in this layer; Ethernet incorporates both this layer and the Data Link Layer. The same applies to other local-area networks, such as Token ring, FDDI, and IEEE 802.11, as well as personal area networks such as Bluetooth and IEEE 802.15.4.
A layer is a collection of conceptually similar functions that provide services to the layer above it and receives service from the layer below it. For example, a layer that provides error-free communications across a network provides the path needed by applications above it, while it calls the next lower layer to send and receive packets that make up the contents of the path.
Contents
1 History
2 Description of OSI layers
2.1 Layer 7: Application Layer
2.2 Layer 6: Presentation Layer
2.3 Layer 5: Session Layer
2.4 Layer 4: Transport Layer
2.5 Layer 3: Network Layer
2.6 Layer 2: Data Link Layer
2.6.1 WAN Protocol architecture
2.6.2 IEEE 802 LAN architecture
2.7 Layer 1: Physical Layer
History
In 1977, 2work on a layered model of network architecture was started, and the International Organization for Standardization (ISO) began to develop its OSI framework architecture. OSI has two major components: an abstract model of networking, called the Basic Reference Model or seven-layer model, and a set of specific protocols.
Note: The standard documents that describe the OSI model can be freely downloaded from the ITU-T as the X.200-series of recommendations.[2] A number of the protocol specifications are also available as part of the ITU-T X series. The equivalent ISO and ISO/IEC standards for the OSI model are available from the ISO, but only some of the ISO/IEC standards are available as cost-free downloads.[3]
All aspects of OSI design evolved from experiences with the CYCLADES network, which also influenced Internet design. The new design was documented in ISO 7498 and its various addenda. In this model, a networking system is divided into layers. Within each layer, one or more entities implement its functionality. Each entity interacts directly only with the layer immediately beneath it, and provides facilities for use by the layer above it.
Protocols enable an entity in one host to interact with a corresponding entity at the same layer in another host. Service definitions abstractly describe the functionality provided to an (N)-layer by an (N-1) layer, where N is one of the seven layers of protocols operating in the local host.
Description of OSI layers
Layer 7: Application Layer
Main article: Application Layer
The application layer is the OSI layer closest to the end user, which means that both the OSI application layer and the user interact directly with the software application. This layer interacts with software applications that implement a communicating component. Such application programs fall outside the scope of the OSI model. Application layer functions typically include identifying communication partners, determining resource availability, and synchronizing communication. When identifying communication partners, the application layer determines the identity and availability of communication partners for an application with data to transmit. When determining resource availability, the application layer must decide whether sufficient network resources for the requested communication exist. In synchronizing communication, all communication between applications requires cooperation that is managed by the application layer. Some examples of application layer implementations include Telnet, Hypertext Transfer Protocol (HTTP), File Transfer Protocol (FTP) , and Simple Mail Transfer Protocol (SMTP).
Layer 6: Presentation Layer
Main article: Presentation Layer
The Presentation Layer establishes a context between Application Layer entities, in which the higher-layer entities can use different syntax and semantics, as long as the Presentation Service understands both and the mapping between them. The presentation service data units are then encapsulated into Session Protocol Data Units, and moved down the stack.
This layer provides independence from differences in data representation (e.g., encryption) by translating from application to network format, and vice versa. The presentation layer works to transform data into the form that the application layer can accept. This layer formats and encrypts data to be sent across a network, providing freedom from compatibility problems. It is sometimes called the syntax layer.
The original presentation structure used the Basic Encoding Rules of Abstract Syntax Notation One (ASN.1), with capabilities such as converting an EBCDIC-coded text file to an ASCII-coded file, or serializing objects and other data structures into and out of XML. ASN.1 has a set of cryptographic encoding rules that allows end-to-end encryption between application entities.
[edit] Layer 5: Session Layer
Main article: Session Layer
The Session Layer controls the dialogues (connections) between computers. It establishes, manages and terminates the connections between the local and remote application. It provides for full-duplex, half-duplex, or simplex operation, and establishes checkpointing, adjournment, termination, and restart procedures. The OSI model made this layer responsible for "graceful close" of sessions, which is a property of TCP, and also for session checkpointing and recovery, which is not usually used in the Internet Protocol Suite. The Session Layer is commonly implemented explicitly in application environments that use remote procedure calls (RPCs).
Layer 4: Transport Layer
Main article: Transport Layer
The Transport Layer provides transparent transfer of data between end users, providing reliable data transfer services to the upper layers. The Transport Layer controls the reliability of a given link through flow control, segmentation/desegmentation, and error control. Some protocols are state and connection oriented. This means that the Transport Layer can keep track of the segments and retransmit those that fail.
Although not developed under the OSI Reference Model and not strictly conforming to the OSI definition of the Transport Layer, the best known examples of a Layer 4 protocol are the Transmission Control Protocol (TCP) and User Datagram Protocol (UDP).[citation needed]
Of the actual OSI protocols, there are five classes of transport protocols ranging from class 0 (which is also known as TP0 and provides the least error recovery) to class 4 (which is also known as TP4 and is designed for less reliable networks, similar to the Internet). Class 0 contains no error recovery, and was designed for use on network layers that provide error-free connections. Class 4 is closest to TCP, although TCP contains functions, such as the graceful close, which OSI assigns to the Session Layer. Detailed characteristics of TP0-4 classes are shown in the following table.
Perhaps an easy way to visualize the Transport Layer is to compare it with a Post Office, which deals with the dispatch and classification of mail and parcels sent. Do remember, however, that a post office manages the outer envelope of mail. Higher layers may have the equivalent of double envelopes, such as cryptographic presentation services that can be read by the addressee only. Roughly speaking, tunneling protocols operate at the Transport Layer, such as carrying non-IP protocols such as IBM's SNA or Novell's IPX over an IP network, or end-to-end encryption with IPsec. While Generic Routing Encapsulation (GRE) might seem to be a Network Layer protocol, if the encapsulation of the payload takes place only at endpoint, GRE becomes closer to a transport protocol that uses IP headers but contains complete frames or packets to deliver to an endpoint. L2TP carries PPP frames inside transport packet.
Layer 3: Network Layer
Main article: Network Layer
The Network Layer provides the functional and procedural means of transferring variable length data sequences from a source to a destination via one or more networks, while maintaining the quality of service requested by the Transport Layer. The Network Layer performs network routing functions, and might also perform fragmentation and reassembly, and report delivery errors. Routers operate at this layer—sending data throughout the extended network and making the Internet possible. This is a logical addressing scheme – values are chosen by the network engineer. The addressing scheme is hierarchical.
The best-known example of a Layer 3 protocol is the Internet Protocol (IP). It manages the connectionless transfer of data one hop at a time, from end system to ingress router, router to router, and from egress router to destination end system. It is not responsible for reliable delivery to a next hop, but only for the detection of errored packets so they may be discarded. When the medium of the next hop cannot accept a packet in its current length, IP is responsible for fragmenting the packet into sufficiently small packets that the medium can accept.
A number of layer management protocols, a function defined in the Management Annex, ISO 7498/4, belong to the Network Layer. These include routing protocols, multicast group management, Network Layer information and error, and Network Layer address assignment. It is the function of the payload that makes these belong to the Network Layer, not the protocol that carries them.
Layer 2: Data Link Layer
Main article: Data Link Layer
The Data Link Layer provides the functional and procedural means to transfer data between network entities and to detect and possibly correct errors that may occur in the Physical Layer. Originally, this layer was intended for point-to-point and point-to-multipoint media, characteristic of wide area media in the telephone system. Local area network architecture, which included broadcast-capable multiaccess media, was developed independently of the ISO work, in IEEE Project 802. IEEE work assumed sublayering and management functions not required for WAN use. In modern practice, only error detection, not flow control using sliding window, is present in modern data link protocols such as Point-to-Point Protocol (PPP), and, on local area networks, the IEEE 802.2 LLC layer is not used for most protocols on Ethernet, and, on other local area networks, its flow control and acknowledgment mechanisms are rarely used. Sliding window flow control and acknowledgment is used at the Transport Layer by protocols such as TCP, but is still used in niches where X.25 offers performance advantages.
Both WAN and LAN services arrange bits, from the Physical Layer, into logical sequences called frames. Not all Physical Layer bits necessarily go into frames, as some of these bits are purely intended for Physical Layer functions. For example, every fifth bit of the FDDI bit stream is not used by the Layer.
WAN Protocol architecture
Connection-oriented WAN data link protocols, in addition to framing, detect and may correct errors. They also are capable of controlling the rate of transmission. A WAN Data Link Layer might implement a sliding window flow control and acknowledgment mechanism to provide reliable delivery of frames; that is the case for SDLC and HDLC, and derivatives of HDLC such as LAPB and LAPD.
IEEE 802 LAN architecture
Practical, connectionless LANs began with the pre-IEEE Ethernet specification, which is the ancestor of IEEE 802.3. This layer manages the interaction of devices with a shared medium, which is the function of a Media Access Control sublayer. Above this MAC sublayer is the media-independent IEEE 802.2 Logical Link Control (LLC) sublayer, which deals with addressing and multiplexing on multiaccess media.
While IEEE 802.3 is the dominant wired LAN protocol and IEEE 802.11 the wireless LAN protocol, obsolescent MAC layers include Token Ring and FDDI. The MAC sublayer detects but does not correct errors.
Layer 1: Physical Layer
Main article: Physical Layer
The Physical Layer defines the electrical and physical specifications for devices. In particular, it defines the relationship between a device and a physical medium. This includes the layout of pins, voltages, cable specifications, Hubs, repeaters, network adapters, Host Bus Adapters (HBAs used in Storage Area Networks) and more.
To understand the function of the Physical Layer in contrast to the functions of the Data Link Layer, think of the Physical Layer as concerned primarily with the interaction of a single device with a medium, where the Data Link Layer is concerned more with the interactions of multiple devices (i.e., at least two) with a shared medium. The Physical Layer will tell one device how to transmit to the medium, and another device how to receive from it (in most cases it does not tell the device how to connect to the medium). Standards such as RS-232 do use physical wires to control access to the medium.
The major functions and services performed by the Physical Layer are:--
Establishment and termination of a connection to a communications medium.
Participation in the process whereby the communication resources are effectively shared among multiple users. For example, contention resolution and flow control.
Modulation, or conversion between the representation of digital data in user equipment and the corresponding signals transmitted over a communications channel. These are signals operating over the physical cabling (such as copper and optical fiber) or over a radio link.
Parallel SCSI buses operate in this layer, although it must be remembered that the logical SCSI protocol is a Transport Layer protocol that runs over this bus. Various Physical Layer Ethernet standards are also in this layer; Ethernet incorporates both this layer and the Data Link Layer. The same applies to other local-area networks, such as Token ring, FDDI, and IEEE 802.11, as well as personal area networks such as Bluetooth and IEEE 802.15.4.
Media
The way on which data travels from Source Computer to the Destination Computer is called Media OR the object which makes a link between Sender and Receiver.
Types of Media
1: Guided Media (Bounded Media)
2: Unguided Media (Unbounded Media)
1: Guided Media: (Cables)
We have three types of Guided Media
Coaxial Cable
Twisted Pair Cable
Fiber Optic Cable
Coaxial Cable
There are two types of Coaxial Cable
Thin net Coaxial Cable
Thick net Coaxial Cable
Thin net Coaxial (10 base 2)
> It is used in base band transmission
> It can flow the data up to 185 to 200 Meter
> We use this type cable in Bus Topology and Ring Topology
> It has a speed of 10 Mbps (Mega bit per second)
> The connector for this cable is called BNC (British Naval Connector)
Thick net Coaxial (10 base 5)
> It is used in base band transmission.
> It can flow the data up to 500 meter.
> It is used in Bus and Ring Topology.
> It has a speed of 10 Mbps
> The connector for this cable is called AUI (Attachment Unit Interface)
Twisted Pair Cable
STP (Shielded Twisted Pair Cable)
UTP (Unshielded Twisted Pair Cable)
There are six Categories available in Twisted Pair Cable
Category Pair Speed Range Usage Connector
Cat 1 4 Mbps 100 Meter Telephone RJ 11
Cat 2 8 Mbps 100 Meter Telephone RJ 11
Cat 3 10 Mbps 100 Meter Network RJ 45
Cat 4 16 Mbps 100 Meter Network RJ 45
Cat 5 100 Mbps 100 Meter Network RJ 45
Cat 5E 100 Mbps 150 Meter Network RJ 45
RJ: Registered Jack
Making of Twisted Pair Cable
We make Twisted Pair Cable in three different ways for Network
1: Cross Cable
2: Straight Cable
3: Roll Over Cable
Cross Cable
Cross Cable is used to connect two same devices like Computer to Computer, hub to Hub or Switch to Switch
Straight Cable
This type of cable is used to connect different devices .It is also used in Star topology. It is used to connect Computer to Hub, Computer to Switch or switch to Router (MAN or WAN)
Roll Over Cable
This type of cable is used to only and only connect Computer to Router; we connect system to Router in order to configuration the Router by the help of IOS (Internet work Operating System).
We have two Standards to make the above three Cables. 568A and 568B
568A 568B
Pin Color Pin Color
1 ------ White Green 1 ------ White Orange
2 ------ Green 2 ------ Orange
3 ------ White Orange 3 ------ White Green
4 ------ Blue 4 ------ Blue
5 ------ White Blue 5 ------ White Blue
6 ------ Orange 6 ------ Green
7 ------ White Brown 7 ------ White Brown
8 ------ Brown 8 ------ Brown
Cross Cable
568A _________________568B
Straight Cable
568A ___________________568A
568B ___________________ 568B
Roll Over Cable
568A ____________________ 568 A-1
Fiber Optic Cable
It is used in LAN, MAN, WAN.
The speed of this cable is up to 2000 Mbps.
It can Flow the Data up to 10 KM.
In the cable instead of conductor there is glass or plastic covered by Fibers.
Data flows in the form of Light.
Light is encoding in digital signals.
It is used in base band transmission.
The connector for this cable is called Fiber Clip.
Types of Media
1: Guided Media (Bounded Media)
2: Unguided Media (Unbounded Media)
1: Guided Media: (Cables)
We have three types of Guided Media
Coaxial Cable
Twisted Pair Cable
Fiber Optic Cable
Coaxial Cable
There are two types of Coaxial Cable
Thin net Coaxial Cable
Thick net Coaxial Cable
Thin net Coaxial (10 base 2)
> It is used in base band transmission
> It can flow the data up to 185 to 200 Meter
> We use this type cable in Bus Topology and Ring Topology
> It has a speed of 10 Mbps (Mega bit per second)
> The connector for this cable is called BNC (British Naval Connector)
Thick net Coaxial (10 base 5)
> It is used in base band transmission.
> It can flow the data up to 500 meter.
> It is used in Bus and Ring Topology.
> It has a speed of 10 Mbps
> The connector for this cable is called AUI (Attachment Unit Interface)
Twisted Pair Cable
STP (Shielded Twisted Pair Cable)
UTP (Unshielded Twisted Pair Cable)
There are six Categories available in Twisted Pair Cable
Category Pair Speed Range Usage Connector
Cat 1 4 Mbps 100 Meter Telephone RJ 11
Cat 2 8 Mbps 100 Meter Telephone RJ 11
Cat 3 10 Mbps 100 Meter Network RJ 45
Cat 4 16 Mbps 100 Meter Network RJ 45
Cat 5 100 Mbps 100 Meter Network RJ 45
Cat 5E 100 Mbps 150 Meter Network RJ 45
RJ: Registered Jack
Making of Twisted Pair Cable
We make Twisted Pair Cable in three different ways for Network
1: Cross Cable
2: Straight Cable
3: Roll Over Cable
Cross Cable
Cross Cable is used to connect two same devices like Computer to Computer, hub to Hub or Switch to Switch
Straight Cable
This type of cable is used to connect different devices .It is also used in Star topology. It is used to connect Computer to Hub, Computer to Switch or switch to Router (MAN or WAN)
Roll Over Cable
This type of cable is used to only and only connect Computer to Router; we connect system to Router in order to configuration the Router by the help of IOS (Internet work Operating System).
We have two Standards to make the above three Cables. 568A and 568B
568A 568B
Pin Color Pin Color
1 ------ White Green 1 ------ White Orange
2 ------ Green 2 ------ Orange
3 ------ White Orange 3 ------ White Green
4 ------ Blue 4 ------ Blue
5 ------ White Blue 5 ------ White Blue
6 ------ Orange 6 ------ Green
7 ------ White Brown 7 ------ White Brown
8 ------ Brown 8 ------ Brown
Cross Cable
568A _________________568B
Straight Cable
568A ___________________568A
568B ___________________ 568B
Roll Over Cable
568A ____________________ 568 A-1
Fiber Optic Cable
It is used in LAN, MAN, WAN.
The speed of this cable is up to 2000 Mbps.
It can Flow the Data up to 10 KM.
In the cable instead of conductor there is glass or plastic covered by Fibers.
Data flows in the form of Light.
Light is encoding in digital signals.
It is used in base band transmission.
The connector for this cable is called Fiber Clip.
NOS (Network Operating System)
Workstation O.S Client O.S Server O.S
Windows NT Workstation Windows NT Workstation Win NT Server
Windows 95 Windows 2000 Professional Win 2000 Server
Windows 97 Windows XP Professional Win 2003 Server
Windows 98 UNIX
Windows 2000 professional Linux
Windows XP professional Novel Netware
Windows NT Workstation Windows NT Workstation Win NT Server
Windows 95 Windows 2000 Professional Win 2000 Server
Windows 97 Windows XP Professional Win 2003 Server
Windows 98 UNIX
Windows 2000 professional Linux
Windows XP professional Novel Netware
Types of Network According to Configuration
1: Workgroup (Peer to Peer Network)
2: Domain (Server Based Network)
Workgroup (Peer to Peer Network)
Ø In this type of Network there is no dedicated (specific) Server.
Ø Every Computer is Server and Client at the same time.
Ø In this network every user is responsible for the security of their System.
Ø Every Computer is known as a Workstation.
Ø No workstation can assign any restriction on any other workstation.
Ø The recommended size of Computers is 10 for this Network. But we can
Connect more then 10 Computers.
Ø Peer to Peer Network is good for sharing of Software and Resources, but there
No security.
Domain (Sever Based Network)
Ø In this type of Network there is a dedicated server which is responsible for the
Ø Management of all other Computers in the Network which are called Clients.
Ø In a Domain all security is centrally administrated by the Server.
Ø Server is responsible to share different kinds of Resources and Software to every Client Computer.
Ø No Client Computer can log on in the Network without the permission of
Server.
Ø A server based network may have thousands of Computers.
2: Domain (Server Based Network)
Workgroup (Peer to Peer Network)
Ø In this type of Network there is no dedicated (specific) Server.
Ø Every Computer is Server and Client at the same time.
Ø In this network every user is responsible for the security of their System.
Ø Every Computer is known as a Workstation.
Ø No workstation can assign any restriction on any other workstation.
Ø The recommended size of Computers is 10 for this Network. But we can
Connect more then 10 Computers.
Ø Peer to Peer Network is good for sharing of Software and Resources, but there
No security.
Domain (Sever Based Network)
Ø In this type of Network there is a dedicated server which is responsible for the
Ø Management of all other Computers in the Network which are called Clients.
Ø In a Domain all security is centrally administrated by the Server.
Ø Server is responsible to share different kinds of Resources and Software to every Client Computer.
Ø No Client Computer can log on in the Network without the permission of
Server.
Ø A server based network may have thousands of Computers.
Types of Network According Area
1: LAN (Local Area Network)
2: MAN (Metropolitan Area Network)
3: WAN (Wide Area Network)
LAN
A Local Area Network is the Network of different Computers in well defines and Small Area like a Network of any organization in one building or cluster of buildings But should be with in 1KM.
MAN
A Metropolitan Area Network is the Network of different remote access buildings
In one city. A city can be large and small. OR the Network of different LANs in one City is called MAN.
WAN
A wide Area Network is Network of different LANs which exist in different cities or Different countries.
2: MAN (Metropolitan Area Network)
3: WAN (Wide Area Network)
LAN
A Local Area Network is the Network of different Computers in well defines and Small Area like a Network of any organization in one building or cluster of buildings But should be with in 1KM.
MAN
A Metropolitan Area Network is the Network of different remote access buildings
In one city. A city can be large and small. OR the Network of different LANs in one City is called MAN.
WAN
A wide Area Network is Network of different LANs which exist in different cities or Different countries.
Resources for making a Network
1 Computers
2 LAN Cards/NIC/Ethernet Card
3 Media (Cable, Waves)
4 Connectors (BNC, AUI, RJ45, Fiber Clips)
5 HUB/Switch (Star Topology)
6 Router (in case of WAN)
7 NOS (Network Operating System)
2 LAN Cards/NIC/Ethernet Card
3 Media (Cable, Waves)
4 Connectors (BNC, AUI, RJ45, Fiber Clips)
5 HUB/Switch (Star Topology)
6 Router (in case of WAN)
7 NOS (Network Operating System)
Benefit of Making Network
1 Fast Communication
2 Sharing data
3 Sharing Resources (Printer, Scanner, Optical Drives, Magnetical Drives etc)
4 Cost effective (by using one device by many computers)
5 Security (Domain)
6 Centralize Administration
7 Electronic Mail
8 Electronic Commerce
9 And many more.
Tuesday, February 24, 2009
Introduction to Network
A network is a collection of computers and devices connected to each other. The network allows computers to communicate with each other and share resources and information.Or A network is a group of computers, printers, and other devices that are connected together with cables. Information travels over the cables, allowing network users to exchange documents & data with each other, print to the same printers, and generally share any hardware or software that is connected to the network. Each computer, printer, or other peripheral device that is connected to the network is called a node.
For making one Network minimum size of Computers should be 2, while maximum
There could be Millions of Computer. In one netwo6rk there could be different Computer
And different NOS (Network Operating System).
There could be Millions of Computer. In one netwo6rk there could be different Computer
And different NOS (Network Operating System).
The Advance Research Projects Agency (ARPA) designed "Advanced Research Projects Agency Network" (ARPANET) for the United States Department of Defense. It was the first computer network in the world in late 1960's and early 1970's.
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